In the 15 years since 9/11, Lower Manhattan has been transformed. The 9/11 Memorial is a poignant centerpiece in the middle of a rejuvenated World Trade Center site, featuring new towers and The Oculus transit center. But while land and infrastructure can be rebuilt, hearts can never fully heal.

That’s especially true for those like Lee Ielpi, whose firefighter son died when trying to save others. But even amid ongoing grief, Ielpi, co-founder of The 9/11 Tribute Center, takes satisfaction in the work his organization does to memorialize the victims of the tragedy.

The NYPD  saluted fallen officers Friday with a spirited parade through the Canyon of Heroes, as vintage patrol cars crawled along Broadway to the swirl of bagpipes. It was as much a celebration of life as a commemoration of crushing loss.